The biological activity of a few compounds which are structurally similar to the compounds of the present invention is known. E.g. the alkylation on the ring nitrogen of 2-(nitroamino)pyridine with .alpha.-haloketones, .alpha.-haloesters and phenylethyl halides has been described in: J. Med. Chem. 14, 988 (1971). The antiinflammatory effect of the compounds obtained has also been described therein.
In the European patent specification No. 9,362 (1980) guanidine-type compounds have been described. A subgroup of these compounds consists of (1-methyl-2-pyridylidene)guanidine derivatives. The substances described in this specification possess hypoglycemic, secretion-inhibiting and cardiovascular activities.
Among the insecticidal compounds described in the published Japanese patent applications Nos. 63,307,857 (1988) and 63,287,764 (1988) as well as in the published European patent application No. 0,259,738 (1988) are 2-(cyanoimino)-and 2-(nitroimino)pyridines substituted on the ring nitrogen by a cyanoalkyl or 3-cyanobenzyl group or by a heterocyclic group through the methylene group.